Cognitive Processing Speed Disability

Diagnostic Features 

Cognitive processing speed disability is the reduced ability to automatically or fluently perform relatively elementary overlearned cognitive tasks, especially when high mental efficiency (e.g., attention and focused attention) is required. In other words, speed of processing is a critical correlate, reflecting the ability to automatize simple or frequently practiced tasks. An example is driving a car. When learning, one is consciously aware and deliberate in each move—but eventually, as the procedure becomes automatic, one can drive a familiar route and arrive at a destination with no memory of having done so.  Driving while being on “automatic pilot” frees the driver’s mind and allows him/her to perform other tasks. 

 

Persons experiencing processing speed disability often have learning difficulties in one or more academic areas due to their inability to process different types of information quickly. Slow processing speed affects a number of cognitive and learning processes such as:

 

Oral or verbal fluency due to slow speech and delays in responding. The person has difficulty to come to a cogent point of view. It may take the person more time to respond to open-ended questions and, in the process, have others wondering whether he is formulating a response to a question, not comprehending the question, or lost in his own thoughts. 

  • Slow reading speed (fluency) restricts formulation of thoughts and affects reading comprehension. Reading speed is the ability to silently read and comprehend connected text (e.g., a series of short sentences; a passage or story) rapidly and automatically (with little conscious attention to the mechanics of reading). 

  •  Writing speed (fluency) impacts on the ability to formulate written texts. Writing speed is the ability to correctly use words or sentences repeatedly, or write words, sentences, or paragraphs, as quickly as possible.

  •  Lack of math fluency has been associated with slow processing speed. Lack of automaticity in math facts contributes to lower achievement in math computations and/or math reasoning. A co-factor contributing to lack of math fluency is poor sustained focal attention (also called vigilance) and restrained working memory capacity often resulting in errors. 

  • Slow processing speed, especially when under time constraints, may impact on the person’s social functional. For example, a person may have trouble with social pressures to perform “faster.” 

Diagnostic Criteria

Efficiency of cognitive processing based on speed of mental activity is diagnosed by means of standardized tests measuring mental processing speed, which is below the 25th percentile on psychometric tasks, such as the Processing Speed Index of the Wechsler Intelligence Scale for Children (WISC-IV) or Wechsler Adult Intelligence Scale (WAIS-II). A cognitive processing disability must be accompanied with significant academic and/or professional difficulties.   

 

Differential Diagnosis

Cognitive processing speed disability, or the efficiency of cognitive processing based on speed of mental activity, needs to be differentiated from other cognitive or learning skills problems contributing to slow information processing. As an example, slow reading speed may result from poor phonological awareness, higher-order cognitive skills or lack of vocabulary knowledge. And, slow writing speed may result from underdeveloped visual fine-motor skills, nonverbal learning disability or developmental delays. 

 

Intervention Strategies

It is important to differentiate the source of the processing speed deficits so as to provide the necessary support and to design proper strategies to increase automaticity in the cognitive areas and learning processes being affected. For instance, in order to increase automaticity with speed of writing, daily timed writing is encouraged. To increase reading speed, possible methods include repeated readings, speed drills, and commercial programs that foster speed reading. 

 

Prevalence and Etiology

Most persons with learning disabilities experience some processing speed difficulty when required to process information through their weakest channel or modality. Children with ADHD often show difficulties on measures of rapid automatized naming. However, a cognitive speed disability, per se, is most often the result of a genetic predisposition, toxic substances, specific brain injuries or physiological diseases.

 

References

Fletcher, J. M., Lyon, G. R., Fuchs, L. S., & Barnes, M. A. (2007). Learning Disabilities. From intervention to intervention.  New York: NY: The Guilford Press.

Levine, M. D. (2001). Developmental variation of learning disorder (2nd Ed.). Cambridge, MA. Educators Publishing Service, Inc. 

Mather, N., & Jaffe, L. E. (2002). Woodcock Johnson III. Report, recommendations, and strategies. New York: NY. John Wiley & Sons, Inc.